'Fracking' for Natural Gas Is Polluting Ground Water, Study Concludes

'Fracking' for Natural Gas Is Polluting Ground Water, Study Concludes

Article excerpt

A Duke University study finds high methane levels in ground water
near where fracking, or hydraulic fracturing, has occurred. Fracking
is a controversial practice to extract natural gas from shale.

Methane levels were 17 times higher in ground water near areas
where shale-gas "fracking" wells had been drilled in Pennsylvania,
compared with areas where no gas drilling had occurred, a new study
has found.

Duke University researchers analyzed methane gas in 68 private
ground-water wells across five counties in Pennsylvania and New
York. The study cited "evidence for methane contamination of
drinking water associated with shale-gas extraction."

In shale-gas extraction, water is mixed with chemicals and sand
and is injected at high pressure deep into shale formations, which
then releases natural gas.

The peer-reviewed study, which is being published in the
Proceedings of the National Academy of Sciences, is one of the first
to conclude that hydraulic fracturing is polluting ground water. And
it's likely to be used as ammunition in court by those opposing
drilling in sensitive watersheds.

The hydraulic fracturing approach has dramatically increased
available US reserves of natural gas by unlocking gas that was
previously trapped in shale formations from the mid-Atlantic to
Texas to Colorado. But environmentalists and local residents have
long claimed that fracking pollutes ground water with methane as
well as with chemicals in the injection fluids.

The Duke researchers said that the presence of methane likely was
due to its escape from faulty drill casings.

While the study found high methane levels, it did not find any
evidence that the chemicals injected at deep levels to fracture the
shale had moved upward to pollute relatively shallow ground water.

"We found no evidence for contamination of drinking-water samples
with deep saline brines or fracturing fluids," the study found. "We
conclude that greater stewardship, data, and possibly regulation are
needed to ensure the sustainable future of shale-gas extraction and
to improve public confidence in its use."

Even so, the study was immediately attacked by natural-gas
industry lobby groups. …

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